1. Field Of The Invention
This invention relates to a method of forming agglutinates in blood samples to permit diagnostic test procedures to be performed on such blood samples. This invention also relates to a non-centrifugal method of typing samples of blood based on the formation of agglutinates in certain of the samples and the determination if agglutinates are present or absent in the samples.
2. Description Of The Prior Art
Blood typing is a form of testing which must be performed by blood banks on all donated blood to ensure that each recipient of blood will be provided with blood that is compatible with the recipient's own blood type. The blood typing reactions which must be performed on donated blood include reactions for the various blood types within the ABO System, and reactions for the various blood types within the Rh System, Systems which are described, respectively, in Chapters 8 and 9 of the Technical Manual of the American Association of Blood Banks, Ninth Edition (1985).
While manual techniques for blood typing are known, including a technique in which reactants are combined on a glass slide or a porcelain tile and are rocked back and forth by hand, or are combined on a heated apparatus frequently referred to as an Rh view box, it is also known hat it is desirable to mechanize blood typing whenever and to the maximum feasible extent, including ABO and Rh typing, as is explained in a publication entitled "Automation of Red Cell Testing" by Sandra S. Ellisor, which appears as Chapter 4 in a publication entitled "Selection of Methods and Instruments For Blood Banks," American Association of Blood Banks (1987). However, as is pointed out in this publication, the mechanical systems for red cell testing which were studied by the author were quite expensive, many involving the need for centrifugation of samples during typing. More information regarding the state of the art in the mechanization of blood typing by blood banks is contained in an article entitled "Automation in Immunohematology" by Steven D. Sosler, which appeared in the December 1985 edition of "Laboratory Medicine." Moreover, and while not set forth in any of the foregoing references, it is known that mechanized blood typing techniques lack sensitivity in typing Rh negative samples, a factor which usually requires manual re-testing of Rh negative samples, which represents approximately 15% of the United States population, and usually with the washing of the tray and the use of secondary reagents, to differentiate Du positive samples from Du negative samples.